Billboard’s Gary Trust wrote about this phenomenon five years ago (see above). Trust’s conclusion: “Pop hits penned by just one writer are now almost completely anachronistic.”

When Trust made that blunt assessment in October 2015, no song written by just one songwriter had reached No. 1 since Pharrell Williams’ “Happy” (which he wrote) 19 months prior. In the five years since Trust’s article, “Perfect” is the only song written by just one writer to reach the top spot.

You don’t have to go back to the days of Irving Berlin and Cole Porter to find a time when it was utterly normal for big hits to be written by just one person. Sixteen songs reached No. 1 on the Hot 100 in 1980. Twelve of them were written by individual songwriters working alone. Even more recently, 10 of the 12 singles that reached No. 1 between August and December 1989 were written by just one person.

The rise of hip-hop, a highly collaborative genre, is partly responsible for the change. So is the prevalence of sampling and interpolating old hits. The writers of the earlier hits are credited, which expands the number of credited songwriters.

But the change has affected all genres. There are eight songwriters listed on Ariana Grande‘s new single “Positions.” It’s Grande’s third consecutive single with eight credited writers, following “Stuck With U” (a collab with Justin Bieber) and “Rain on Me” (a collab with Lady Gaga). Grande’s two singles immediately before these each had seven writers. The record for a Grande single was “7 Rings,” which had 10 credited writers (including Rodgers & Hammerstein, whose “My Favorite Things” was interpolated in the song).

We can see the change in the Grammy Awards as well. Five of the first 10 winners for song of the year (from 1958 to 1967) went to just one individual. None of the last 10 have. The last song written by just one songwriter to win song of the year was Amy Winehouse’s “Rehab,” which won 13 years ago. The 2018 award went to Bruno Mars’ “That’s What I Like,” which was co-written by eight songwriters — a category record.

The trend has even extended to country music, one of the most traditional genres.

It took a village (16 songwriters) to come up with the five songs that are vying for song of the year at the Country Music Awards on Nov. 11. This marks a big change from the early years in that category. The first 10 CMA winners for song of the year (from 1967 to 1976) were all written by just one songwriter. Just three of the last 10 winners were written by one songwriter.

Here’s a decade-by-decade recap, showing first, the percentage of all the singles that reached No. 1 on the Hot 100 in that decade that were written by just one person; then the raw numbers supporting that percentage; and finally the longest-running No. 1 hit from that decade that was written by just one person (because stats are fun, but remembering the hits of the period under discussion is even more fun).

The 1950s: 39%

This measures from the launch of the Hot 100 on Aug. 4, 1958, through the last week of the decade. In that time, there were 23 No. 1 hits. Nine were written by just one person.

Longest-running No. 1 of this period that was written by just one writer: Frankie Avalon’s “Venus” (written by Ed Marshall), five weeks at No. 1 in 1959.

The 1960s: 29%

203 singles reached No. 1 in the ‘60s. 58 were written by just one person.

Longest-running No. 1 of the decade that was written by just one writer: Percy Faith’s instrumental smash “The Theme From ‘A Summer Place’” (composed by Max Steiner), nine weeks at No. 1 in 1960. Longest-running No. 1 that had both music and lyrics by just one writer: The Monkees’ “I’m a Believer” (written by Neil Diamond), seven weeks at No. 1 in 1966-67.

The 1970s: 44%

253 singles reached No. 1 in the ‘70s. 112 were written by just one person.

Longest-running No. 1 of the decade that was written by just one writer: Debby Boone’s “You Light Up My Life” (written by Joe Brooks), 10 weeks at No. 1 in 1977. This was also the decade’s longest running No. 1 hit, period.

The 1980s: 42%

231 singles reached No. 1 in the ‘80s. 98 were written by just one person.

Longest-running No. 1 of the decade that was written by just one writer: Diana Ross & Lionel Richie’s “Endless Love” (written by Richie), nine weeks at No. 1 in 1981.

The 1990s: 24%

140 singles reached No. 1 in the ‘90s. 34 were written by just one person.

Longest-running No. 1s of the decade that was written by just one writer (a tie): Whitney Houston’s “I Will Always Love You” (written by Dolly Parton), 14 weeks at No. 1 in 1992-93, and Boyz II Men’s “I’ll Make Love to You” (written by Babyface), 14 weeks at No. 1 in 1994.

The 2000s: 6%

129 singles reached No. 1 in the ‘70s. Eight were written by just one person.

Longest-running No. 1 of the decade that was written by just one writer: OutKast’s “Hey Ya!” (written by Andre “3000” Benjamin), nine weeks at No. 1 in 2003-04.

The 2010s: 4%

116 singles reached No. 1 in the ‘10s. Just five were written by just one person.

Longest-running No. 1 of the decade that was written by just one writer (a tie): Rihanna feat. Calvin Harris’ “We Found Love” (written by Harris), 10 weeks at No. 1 in 2011-12, and Williams’ “Happy” (written by Williams), 10 weeks at No. 1 in 2014.

The 2020s: 0%

17 singles have reached No. 1 so far in the ‘20s. None were written by just one person.